This invention relates to a method for manufacturing fabrics with a rib structure, in particular false boucle fabrics, whereby on a weaving machine, by inserting weft threads in successive sheds between warp threads of a series of warp thread systems, a fabric is formed with sets of at least two weft threads running one above the other, whereby in each warp thread system two pattern warp threads opposite each other, respectively along the upper side and the lower side of the fabric, form a number of ribs whereby these pattern warp threads alternately along their respective fabric side are rib-formingly passed around over one or several sets of weft threads and are interlaced in the fabric.
This invention also relates to fabrics with a rib structure which are manufactured according to such a method, in particular false boucle fabrics, comprising a number of sets of at least two weft threads running one above the other which are inwoven by warp threads of a series of warp thread systems, of which two pattern warp threads opposite each other, respectively along the upper side and the lower side of the fabric, form a number of ribs whereby these pattern warp threads alternately along their respective fabric side are rib-formingly passed around over one or several sets of weft threads and are interlaced in the fabric.
A fabric with a rib structure which approximates the appearance of a loop pile fabric or boucle fabric, is called a false boucle fabric.
In this specification and in the claims of this patent application the terms "lower side" and "upper side" of a fabric are only used to indicate the two different sides of the fabric. The aforesaid terms must be interpreted in the sense of "the one side" and "the other side". The literal meaning of the terms "upper side" and "lower side" may therefore not give rise to any restriction on this invention.
According to a known weaving method for manufacturing a false boucle fabric, which has the above mentioned characteristics, tension warp threads are inwoven stretched in the fabrics and in each weft insertion cycle on the weaving machine two weft threads are simultaneously inserted one above the other. In successive insertion cycles the two weft threads are in relation to the tension warp threads alternately inserted along the upper side and along the lower side of the fabric.
In warp thread systems located next to each other a first and a second pattern warp thread of a different color are provided in order to be able to make a design or a pattern visible with the two colors along the upper side of the fabric.
The first pattern warp thread is alternately rib-formingly passed over the two weft threads along the upper side of the fabric and interlaced between the two weft threads along the lower side of the fabric, in order to achieve a rib structure on the upper side of the fabric and to form the design or the pattern. The second pattern warp thread is interlaced opposite the first pattern warp thread, alternately between the two weft threads along the upper side of the fabric and passed around over the two weft threads along the lower side of the fabric. The color of the second pattern warp thread is then not visible on the upper side, but it is on the lower side of the fabric. The second pattern warp thread forms a rib structure on the lower side of the fabric. With these known fabrics the weft threads are inwoven by the pattern warp threads. With each insertion cycle a rib line is produced (alternately along the upper side and along the lower side of the fabric).
Both the upper side and the lower side of this known fabric have a rib structure. On the lower side of the fabric a type of negative (with swapped colors) is obtained of the two-colored design which is visible on the upper side of the fabric.
A disadvantage of this method is that the fabrics thus produced cannot closely approximate the appearance of the real loop pile fabrics or boucle fabrics. Furthermore the designs or patterns provided on these fabrics only have two different colors.